Rapid connection coupling

ABSTRACT

The invention concerns a rapid connection coupling (10) for transferring gases and/or liquid, in particular for coolant filling operations in air conditioning systems. The coupling in question comprises the following elements: a tubular housing (11), an outer sliding sleeve (18) which can slide relative to the housing (11); a number of radially expanding collet chuck elements (15) mounted on the housing (11) and provided with an engaging contour (17) which facilitates connection to a matching connection nipple (30); and a sealing piston (22) capable of sliding centrally inside the housing (11), the said sealing piston being brought into contact with the connecting nipple (30). To ensure easy handling, it is proposed that a sliding ring (40) which can slide independently and is acted on by a spring should be provided between the sealing piston (22) and the collet chuck elements (15); the sliding ring engages with the collet chuck elements (15) and keeps them in the open position when the plug-in connection coupling (10) is in the uncoupled position, and is so fitted as to be capable during the coupling action of sliding with the sealing piston (22) to break the engagement with the collet chuck elements (15).

DESCRIPTION

This invention relates to a rapid connection coupling for transferringgaseous and/or liquid fluids, especially for charging coolants inair-conditioning systems.

A reliable, tight and rapidly connected plug-in coupling should beeffected with such rapid connection couplings for transferring a fluidfrom a pressure source, for example a refill cylinder. Simple,problem-free operation of the rapid connection coupling is particularlyimportant, so that problem-free handling is facilitated even underunfavourable conditions, such as dangerous fluids or at high connectionpressures.

Such a rapid connection coupling is described in EP-A 0 340 879, whereinthe rapid connection coupling has a housing with a fluid inlet and afluid outlet, while a plurality of valves are provided in order toensure reliable sealing of the rapid connection coupling right up tocomplete production of the connection. These valves are operated in aspecific, predetermined sequence after fitting of the rapid connectioncoupling, where the outlet valve is opened at first by pushing the rapidconnection coupling on to a connection nipple, then with furthermovement of a control lever, the jaws are closed and finally the inletvalve is opened. The control lever engages via an eccentric shaft withthe sliding sleeve for actuating the jaws and also with a centralsealing piston, which also opens up the fluid inlet after completedconnection of the plug-in coupling. Although this provides aparticularly reliable connection facility, the structure of thiscoupling is relatively expensive in account of the many components. Inaddition handling is relatively complicated since actuation of thecontrol lever is necessary as well as plugging in the coupling, so thatone-handed operation is hardly possible.

Such a rapid connector is further known from WO-A 93/20378 of theapplicants, especially for charging from gas cylinders, wherein a rapidconnection arrangement is provided in the region of the outlet, in theform of jaws with an engagement profile. A hollow sealing piston slidingin the coupling housing is also described here and is connected throughan actuating device coupled to a sliding sleeve for closing and openingthe jaws. Separate actuation of the actuating device in the form of alever is also necessary here, so that handling of this rapid connectoris also susceptible of improvement.

Accordingly the invention is based on the object of providing a rapidconnection coupling of the kind initially described which facilitatesreliable and especially simple handling with a simple structure.

This object is met by a rapid connection coupling according to thefeatures of claim 1. Preferred developments of the invention are thesubject matter of the dependent claims.

The proposed rapid connection coupling is distinguished by a small partscount, simple manufacture and an especially simple operation, which isin addition particularly reliable. In particular, in the preferredembodiment for charging air-conditioning systems with coolant, escape ofthe gas or liquid coolant is reliably avoided when connecting orreleasing the rapid connection coupling. This is especially importantfor protection of the environment, since fluorinated/chlorinatedhydrocarbons are frequently used in such air-conditioning systems. Withthe connection couplings in use today a substantial volume of gas islost in each charging operation, which is present in the hose betweenthe refill gas cylinder and the connection coupling and can escape whencoupling up or uncoupling.

It should be noted that the proposed rapid connection coupling issuitable for various connections, in particular for connection nippleswith an external thread. However other profile shapes such as grooves orbeads on the connection nipple can be provided for connection of thecoupling, the opposed jaw shape being correspondingly formed. By meansof the sealing piston slidably movable in the housing reliableengagement of the jaws is facilitated, since the engagement profile ofthe jaws automatically interlocks with the turns of the thread or othersuitable mating engagement profile through the slight ability to move ofthe sealing piston. This is especially important since the correspondingconnection nipple, e.g. for an air-conditioning system, can be ofrelatively simple construction and nevertheless because of the slightability of the sealing piston to move axially between the engagementprofile of the jaws and the sealing surface, the rapid connectioncoupling engages reliably in the connection profile of the connectionnipple. In addition excessive wear or damage to the connection profileboth on the coupling side and the nipple side is reliably avoided.

The realisation of the rapid connection coupling by means of an outersliding sleeve is especially important, so that reliable and rapidone-handed operation of the rapid connection coupling is facilitated inan especially simple manner.

An embodiment will be described and explained in more detail below withreference to the accompanying drawings, in which:

FIG. 1 is a side view of a rapid connection coupling for a connectionnipple with an external thread as the connection profile, wherein therapid connection coupling is shown in longitudinal half section and inthe position shortly before connection;

FIG. 2 is a similar view of the rapid connection coupling but in thefully connected position on the connection nipple.

A preferred embodiment of a rapid connection coupling 10 is shown inFIG. 1, shortly before the connection to a connection nipple 30. Therapid connection coupling 10 comprises a tubular housing 11, where theright end here serves as the inlet 12 and the left end as the outlet 13for feeding on the transferred fluid to the connection nipple 30. Theinlet 12 to the housing 11 has a connection adaptor 14, which is screwedinto the housing 11 and is sealed relative to the housing 11 by a seal14a. The connection adaptor 14 also comprises a thread 14b at its endhere on the right, to which a hose or a pipeline for supplying thetransferred fluid can be connected. The connection adaptor 14 can bedesigned to match the fluid to be transferred, especially the currentlydesired feed angle, through-flow cross-section, etc.

On the end opposite the connection adaptor 14, here the outlet 13, thereare provided several jaws 15 arranged in tubular form and which areradially spread in the position shown here shortly before plugging on tothe connection nipple 30, as is also shown in the previously recitedWO-A 93/20378 for example. The elongated jaws 15, of which at leastthree and in general six jaws are arranged around the housing 11, arehooked in an annular groove 11a of the housing 11 at their ends here onthe right and are biased by an annular spring 16 so that the jaws 15 areradially spread. At the end here to the left, on the inwardly offsetsurface, the jaws 15 each have an interlocking engagement profile 17formed in correspondence with the connection profile 31 of theconnection nipple 30, so that in the design with an external thread onthe connection nipple 30, a correspondingly formed inner thread isopposed on the radially inwardly directed surfaces of the engagementprofile 17.

An outer sliding sleeve 18 is provided around the jaws 15 and is guidedon the cylindrical outer surface of the housing 11 and is biased by arelatively weak compression spring 19 in the direction of the connectionnipple 30. The compression spring 19 abuts the connection adaptor 14 orthe housing 11 via an abutment ring 20 and a circlip 21.

A sealing piston 22 is guided on the peripheral surface of the housing11 disposed towards the outlet 13 and comprises a sealing ring 23 at itsfront end for engagement on a conically-formed sealing surface 32 of theconnection nipple 30. The sealing piston 22 is sealed relative to thejaws 15 by means a sealing ring 24 fitted on the front end of thehousing 11, so that gaseous and/or liquid fluid flowing essentiallyalong the central axis of the plug-in coupling 10 cannot escape to theoutside.

Furthermore, a check valve 25 fitted centrally in the housing 11 is ofgreat importance and is sealed relative to a sealing surface 27 on thehousing 11 by means of a sealing ring 26 in the closed position. Thecheck valve 25 is biased by a compression spring 28, which is guided bya centering insert 29 in the connection adaptor 14 and abuts the latter.Through this check valve 25 it is ensured that the fluid fed through theconnection adaptor 14 cannot flow out even with the connecting valve onthe refill cylinder or the like open in the uncoupled position or justbefore the connection of the rapid connection coupling 10 to theconnection nipple 30, as shown here.

The check valve 25 has a centrally arranged valve plunger 25b facingtowards the outlet 13, with a conical centering depression 25a at thefront end. On plugging the rapid connection coupling 10 on to theconnection nipple 30, this centering depression 25a cooperates with apin 33 projecting out of the connection nipple 30, whereby the pin ispressed in along the connection nipple axis on attachment and herebyactuates a check valve 34 shown in broken lines. The check valve 25 ofthe rapid connection coupling 10 further comprises a stem 25c oppositethe centering insert 29, which serves to guide the compression spring 28and together with a stop 29a of the centering insert 29 limits the axialstroke of the check valve 25.

Of particular importance is a sliding ring 40 which is guided on theouter periphery of the sealing piston 22 and is biased by a compressionspring 41. The compression spring 41 abuts a shoulder 11b of the housing11. As can be seen from the drawing, the end of the sliding ring 40 ofnarrow form facing towards the outlet 13 engages on the inner surface ofthe jaws 15, whereby they are held in their radially spread, openposition. The sliding ring 40 is urged by the compression spring 41against the inwardly offset region of the jaws 15, whereby a stop to thesliding movement of the sliding ring 40 on the sealing piston 22 is alsoeffected. Since the sealing piston 22 can slide a little axially,depending on the position and engagement conditions of the engagementprofile 17 in the opposed profile 31 of the connection nipple 30, astepped entraining profile 50 is provided between the sliding ring 40and the sealing piston 22, so that a certain capacity for relative axialmovement of these two components is provided.

The connected position of the rapid connection coupling is shown in FIG.2. As can be seen, on plugging the rapid connection coupling 10 on tothe connection nipple 30, the centering depression 25a is brought intocontact with the pin 33 projecting from the connection nipple 30, sothat these move substantially simultaneously in opposite directions,depending on the spring design. The sealing ring 23 also comes intoengagement with the sealing surface 32, so that escape of fluid, whichmight arise at the check valve 34 of the connection nipple 30, isavoided. Furthermore, the sealing piston 22 is displaced to the right bythe abutment of the sealing ring 23 on the sealing surface 32, until theshoulder projecting from the outer periphery in the region of theentraining profile 50 comes into engagement with the sliding ring 40.The sealing piston 22 is thereby displaced to the right together withthe sliding ring 40 against the spring force of the compression spring41. After a small movement of a few millimeters the inner surfaces ofthe jaws 15 bearing on the outer surface of the sliding ring 40 arefreed from their blocked position, so that they can snap inwardly, sothat the engagement profile 17 can engage with the correspondinglyformed connection profile 31 of the connection nipple 30. Practicallysimultaneously the sliding sleeve 18 becomes free for axial movement tothe left, since the sliding sleeve 18 is biased by the compressionspring 19. By virtue of its axial movement, the sliding sleeve 18engages over the outer ends of the jaws 15, so that they are retainedinterlocked in their engaged position on the connection nipple 30.

It should be noted that in the connected position shown in FIG. 2, thesealing piston 22 is axially movable in the millimeter range. It is ofsignificant importance that there is a piston annular surface 22a, whichhas a greater effective area than in the region of the contactingsurface between the sealing ring 23 and the sealing surface 32. Throughthis it is ensured that, with fluid flow as shown in broken linessubstantially along the central axis of the rapid connection coupling10, the sealing piston 22 with its sealing ring 23 is pressed even morestrongly against the sealing surface 32 as the pressure increases. Thisprovides a servo-action, i.e. a stronger force of application of thesealing ring 23 with increasing fluid pressure and thus a particularlyreliable sealing of the rapid connection coupling 10.

In order to release the rapid connection coupling 10 and thus return tothe open position according to FIG. 1 from the attached positionaccording to FIG. 2 the sliding sleeve 18 is retracted manually by meansof knurling or suitable profiling of the outer surface. After a shortmovement the jaws 15 can again spread radially, whereby the sliding ring40 is simultaneously displaced to the left towards the outlet end 13under the action of the compression spring 41. On account of the axialplay in the region of the entraining profile 50 this sudden movement ofthe sliding ring 40 can take place independently of the secureengagement of the sealing ring 23 of the sealing piston 22. Thus, beforethe sealing contact between the sealing piston 22 and the sealingsurface 32 is broken the check valve 25 is closed on account of theaxial play of the valve plunger 25b relative to the piston annularsurface 22 a serving as an abutment surface and the pin 33 is alsoallowed to project externally again, so that the check valve 34 of theconnection nipple 30 is also simultaneously closed. By virtue of thispractically simultaneous sequence there is a very rapid closing of thecheck valves, so that no volume of fluid can escape. The design of thesliding ring 40 is especially important to this, since the spreadingmovement of the jaws 15 is assisted by the end facing the outlet 13, sothat the release of the rapid connection coupling takes placepractically at a stroke, so that damage to the engagement profile 17 orthe connections profile 31 is avoided. The sliding ring 40 also allowssecure plugging of the rapid connection coupling 10 on to the connectionnipple 30, whereby the jaws 15 are only closed when the sealing contactbetween the sealing surface 32 and the sealing ring 22 is ensured, sincethe open position of the jaws 15 is maintained until the open positionof the jaws 15 is enabled by the axial displacement of the sealingpiston 22 and the entrainment of the sliding ring 40 derived therefromin direct sequence, in order to produce the connection practically at astroke.

We claim:
 1. A rapid connection coupling for transferring fluidsincluding charging coolants in air-conditioning systems, comprising:atubular housing having a longitudinal axis; an outer sliding sleeveencircling and slidably mounted relative to the housing to move alongthe longitudinal axis between a coupled and uncoupled position of therapid connection coupling; a plurality of jaws attached to the housingand which can spread radially, the jaws having an engagement profile forconnection to a correspondingly formed connection nipple, the sleevesliding over the jaws and being sized so the sleeve pushes against thejaws to urge the jaws to couple with the nipple when the sleeve is inthe coupled position; a sealing piston sliding along the longitudinalaxis relative to the housing for sealing engagement with the connectionnipple; a spring-biased sliding ring sliding axially independentlybetween the sealing piston and the jaws, the spring located so that iturges the ring to engage the jaws in the uncoupled position of the rapidconnection coupling to hold the jaws in an open position, the ring beingfurther slidably mounted to move during a coupling movement togetherwith the sealing piston to free the engagement with the jaws, the ringand sealing piston having correspondingly located surfaces which engagewhen the coupling nipple is inserted into the jaws and moves the sealingpiston to achieve the coupling.
 2. A rapid connection coupling accordingto claim 1, further comprising a compression spring acting on thesealing piston and said spring acting on said sliding ring comprises acompression spring.
 3. A rapid connection coupling according to claim 2further comprising entraining profile means for providing axial playbetween the sealing piston and the sliding ring.
 4. A rapid connectioncoupling according to claim 2 wherein the sealing piston is guided onthe outer surface of the housing and a piston annular surface isprovided and which extends into a flowpath of the fluid passing thoughthe coupling when in use.
 5. A rapid connection coupling according toclaim 4, wherein a seal is carried by the piston and the engagement ofthe contacting nipple with the seal carried by the piston forms anaxially opposed seal having an axially opposed sealing area, and thepiston annular surface has a greater effective surface than the axiallyopposed sealing surface.
 6. A rapid connection coupling according toclaim 2, wherein the sliding ring is guided on the outer surface of thesealing piston.
 7. A rapid connection coupling according to claim 2,further comprising check valve means placed centrally in the housing andin sealing engagement with the housing for ensuring that fluid cannotflow the housing when the connecting nipple is in an uncoupled positionor during coupling.
 8. A rapid connection coupling according to claim 1further comprising entraining profile means for providing axial playbetween the sealing piston and the sliding ring.
 9. A rapid connectioncoupling according to claim 8 wherein the sealing piston is guided onthe outer surface of the housing and a piston annular surface isprovided and which extends into a flowpath of the fluid passing thoughthe coupling when in use.
 10. A rapid connection coupling according toclaim 8, wherein the sliding ring is guided on the outer surface of thesealing piston.
 11. A rapid connection coupling according to claim 8,further comprising check valve means placed centrally in the housing andin sealing engagement with the housing for ensuring that fluid cannotflow the housing when the connecting nipple is in an uncoupled positionor during coupling.
 12. A rapid connection coupling according to claim 1wherein the sealing piston is guided on the outer surface of the housingand a piston annular surface is provided and which extends into aflowpath of the fluid passing though the coupling when in use.
 13. Arapid connection coupling according to claim 12, wherein a seal iscarried by the piston and the engagement of the contacting nipple withthe seal carried by the piston forms an axially opposed seal having anaxially opposed sealing area, and the piston annular surface has agreater effective surface than the axially opposed sealing surface. 14.A rapid connection coupling according to claim 12, wherein the slidingring is guided on the outer surface of the sealing piston.
 15. A rapidconnection coupling according to claim 12, further comprising checkvalve means placed centrally in the housing and in sealing engagementwith the housing for ensuring that fluid cannot flow the housing whenthe connecting nipple is in an uncoupled position or during coupling.16. A rapid connection coupling according to claim 15, wherein thepiston annular surface is opposite a valve plunger of the check valve.17. A rapid connection coupling according to claim 1, wherein thesliding ring is guided on the outer surface of the sealing piston.
 18. Arapid connection coupling according to claim 1, further comprising checkvalve means placed centrally in the housing and in sealing engagementwith the housing for ensuring that fluid cannot flow the housing whenthe connecting nipple is in an uncoupled position or during coupling.19. A method for rapid connection coupling for transferring fluidsincluding charging coolants in air-conditioning systems, the couplinghaving a tubular housing with an outer sliding sleeve slidably mountedrelative to the housing, the coupling having a plurality of jawsattached to the housing so the jaws can be spread radially, with thejaws having an engagement profile for connection to a correspondinglyformed connection nipple, comprising the steps of:slidably mounting aspring-biased sliding ring between the sealing piston and the jaws;sliding the ring to engage the jaws in an uncoupled position of therapid connection coupling to hold the jaws in an open position; andslidably mounting the ring to move during the coupling movement togetherwith the sealing piston to free the engagement with the jaws.
 20. Arapid connection coupling for transferring fluids such as chargingcoolants in air-conditioning systems, comprising:a tubular housing; jawsmeans attached to the housing for spreading radially to connect to aconnection nipple; sliding sleeve means mounted outside the housing formoving the jaws into a coupled position and locking them in thatposition, and for unlocking the jaws to permit uncoupling; sealingpiston means sliding relative to the housing for forming a sealingconnection with the connection nipple in the coupled position; slidingring means interposed between the sealing piston means and the jawsmeans to hold the jaw means in an uncoupled position and cooperatingwith the piston means to free the jaw means for movement to a coupledposition; and check valve means in the housing for preventing fluid flowthrough the housing when the jaws are in an uncoupled position andduring coupling.